. this is incredible technology you have at your disposal in these situations. >> yes. those are assets that the watertown police department doesn't normally have. but to sit in the command post with the federal agencies, and be able to watch it on a down link right there, as it played out. it was incredible. what technology does for law enforcement now. >> one of the reports that's been repeated quite often the last 24 hours is that, dzhokhar ran over and killed his older brother tamerlan when he got away on that night after the gun fight. is that your understanding? >> that is exactly my understanding. what occurred is the older brother charged at one of our officers shooting at him. they ended up within ten feet of each other exchanging gunfire. he ran out of ammunition and our officers tackled him, put him to the ground. two other officers were on top of him and that's when the brother came roaring down the street with the car jacked suv with the full intent of killing my police officers. they were lucky enough to dive out of the way. but the brother was run over at that same time.